The present invention is generally directed to ensuring selection of the correct-size wheel bearing. Specifically, the present invention provides an apparatus for correctly identifying and storing wheel bearings and a method for using that apparatus.
Wheel bearings are manufactured in a variety of different sizes. However, different sizes of wheel bearings can often have very similar dimensions. The similarity between different size wheel bearings can result in the use of the wrong type of wheel bearing in a wheel assembly. This problem is of particular importance in the airline industry. Different models of aircraft usually require different types of wheel bearings in their wheel assemblies. Typically, there are many different types of wheel bearings to choose from in selecting the correct type for a particular model of aircraft. In most aircraft, there are two wheel bearings in each wheel assembly, one called the inboard bearing (IB) and the other the outboard bearing (OB). Not only does bearing size vary among aircraft models, but each wheel bearing in the pair within a wheel assembly is generally a different size.
There can be five variables that distinguish the different types of wheel bearings. The five variables are the (1) outside diameter of the wheel bearing, (2) the inside diameter of the wheel bearing, (3) the number of rollers, (4) the taper angle of the outer circumference of the bearing, and (5) the height of the bearing. Generally, at least four of these five potential variables are required to be known to distinguish one bearing from another. Of the different types of bearings, several are so close in size that the differences in their dimensions are not easily discernable with the human eye. Although many of the bearings are very close in size, it is essential that a mechanic use a bearing of the correct size in the wheel assembly. Using a bearing that is only slightly different from the correct size bearing can cause a failure in the bearing due to the significant stress in the wheel assembly during take-off and landing of aircraft.
Each of the different types of bearings are stamped with a serial number that identifies the bearing. In the conventional approach to selecting the correct bearing, the mechanic checks the serial number on each bearing before installing it in the wheel assembly. The problem with this approach is that humans occasionally make errors and could inaccurately read the serial number stamped on the bearing. This potential for inaccuracy is compounded by the fact that the serial numbers used on typical aircraft wheel bearings are generally several digits long and use many of the same digits. One attempt at solving this problem was the use of a xe2x80x9cgo-no goxe2x80x9d gauge. The xe2x80x9cgo-no goxe2x80x9d gauge was simply a piece of material cut to the size of the inside diameter of a particular wheel bearing. When selecting a wheel bearing, a mechanic would slide the wheel bearing onto the xe2x80x9cgo-no goxe2x80x9d gauge to insure that it was the correct size. However, the xe2x80x9cgo-no goxe2x80x9d gauge is limited in that it only measures one of the five potential variables that distinguish wheel bearings. For example, a mechanic could use a wheel bearing with the correct inside diameter, according to the xe2x80x9cgo-no goxe2x80x9d gauge, but an incorrect outside diameter.
In view of the foregoing, there is a need in the art for an apparatus that can accurately differentiate various sizes of wheel bearings. There is a further need for an apparatus that protects a wheel bearing from damage or contamination while it is stored until subsequent use in a wheel assembly. There is also a need for a method for efficiently employing the apparatus in a machine shop environment where wheel assemblies are taken apart and reconstructed. The present invention can facilitate selection of the correct size of wheel bearing for insertion in the wheel assembly of an aircraft.
The present invention comprises a device and method for insuring that a mechanic uses the correct size wheel bearing in an aircraft wheel assembly. For one aspect, the invention comprises a mold with one or more recesses that accurately fit to the dimensions of a particular wheel bearing. The mold can be made of any material that can be easily shaped such as plastic or sheet metal. Accordingly, molds can be created with different size recesses for each type of wheel bearing and only one wheel bearing can fit in each recess in a mold. If any of the variables that distinguish a wheel bearing do not correspond to the mold, the wheel bearing will not properly fit within the recess and it will be apparent to the mechanic that it is a bearing of incorrect size.
For another aspect, the invention comprises a mold with a circular recess shaped to fit only one size of wheel bearing. The recess comprises an outer wall contoured to fit the rollers of the wheel bearing. The recess also comprises a hub at the center of the recess. The recess can be designed such that the top surface of the hub is level with the top surface of the wheel bearing when a wheel bearing of the correct size is placed in the recess. The mold can also comprise finger recesses to facilitate removal of the wheel bearing from the recess. A removable cover can be attached to the mold to protect the wheel bearing while it sits in the mold. Markings on the mold can identify the serial number and type of wheel bearing and the type of aircraft it is designed for.
For yet another aspect, the present invention comprises a system for storing a wheel bearing in a wheel bearing mold until it is needed for a wheel assembly. The wheel bearing can be either a new bearing from the manufacturer or a recycled bearing previously used in another wheel assembly. The system comprises packaging the wheel bearing in a mold with a cover and storing the packaged wheel bearing in a rack of wheel bearings of the same size.
In yet another aspect, the present invention comprises a method that facilitates installing the correct size wheel bearing in a wheel assembly. When a mechanic needs a wheel bearing, she can select a wheel bearing mold from a rack of wheel bearings of the desired size. The wheel bearing model number and vehicle model can be printed on the mold for verifying that it is correct. The mechanic can remove the correct wheel bearing from the mold and install it in the wheel assembly.
These and other aspects of the invention will be described below in connection with the drawing set and the appended specification and claim set.